网站登录简单验证码

 1 ?public string BindCode(int length) 2 ????????{ 3 ????????????string Vchar = "1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z"; 4 ?5 ????????????string[] VcArray = Vchar.Split(new Char[] { ‘,‘ }); ?????????8 ????????????Random rand = new Random(); 10 ???????????11 ????????????int a;12 ????????????List<int> result = new List<int>();13 ????????????string numlist = string.Empty;14 15 ????????????for (int i = 1; i < length + 1; i++)16 17 ????????????{18 ????????????????a = rand.Next(1, VcArray.Length); ?//设置范围。我这里是取数据库的数据1~n19 ????????????????if (result.Contains(a))20 ????????????????{21 ????????????????????i = i - 1; //有重复值,重新再来一次,循环次数减一次22 ????????????????}23 ????????????????else24 ????????????????{25 ????????????????????numlist += VcArray[a]; ?//无重复值，就添加在集合内26 ????????????????}27 ????????????}28 ?????????29 ????????????return numlist; ????????30 ????????}

1 ?protected void Page_Load(object sender, EventArgs e)2 ????????{3 ????????????if (!IsPostBack)4 ????????????{5 ????????????????Barcoded.Text = BindCode(4);6 ????????????}7 ????????}